Forgive me this is probably a stupid question but in either instance why would you want to do that? The manufacturers had a certain car in mind when they built it. Why not buy a model whose chassis is built with both weight distribution and aerodynamics to accommodate a given drivetran?
Stick it in reverse. You're welcome...
{Cy}
Stick it in reverse. You're welcome...
{Cy}
Sadly you cant. It would be really cool if you could do Drivetrain swaps. AWD to RWD sounds good!
What's AWD?